RF-to-DC Power Converter with Feedback Bias Control
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Solution Overview
Problem
Existing RF-to-DC power converters, such as fully cross-coupled rectifiers, suffer from efficiency degradation at high RF power levels due to reverse leakage, limiting their operating range and overall power conversion efficiency, while diode-based rectifiers have poor sensitivity at low input power levels.
Innovation Solution
A wide range RF-to-DC power converter architecture that employs a fully cross-coupled rectification circuit with a smart DC biasing mechanism using feedback branches and a power management unit to control the gates of forward rectifying transistors, limiting reverse leakage and maintaining sensitivity across a broader range of RF input power levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fully cross-coupled rectification circuit is used, then sensitivity at low input power levels is improved, but efficiency at high RF power levels deteriorates due to reverse leakage
Solution Approach 1:
The patent implements dynamic biasing control where the bias signals supplied to the gates of forward rectifying transistors are dynamically adjusted based on feedback from the output voltage. This allows the rectification circuit to adapt its operating characteristics in real-time, maintaining optimal sensitivity at low power levels while suppressing reverse leakage at high power levels through adaptive bias modulation.
Solution Approach 2:
The patent employs a feedback mechanism where the output voltage is monitored and used to control the bias signals applied to the rectifying transistors. This feedback loop enables the system to automatically adjust its operating point, preventing reverse leakage current by modulating the gate bias according to the actual output conditions, thereby resolving the efficiency degradation problem at high RF power levels.
2Loss of energy
If diode-based rectification is used, then efficiency at high RF power levels is improved, but sensitivity at low input power levels deteriorates
Solution Approach 1:
The patent changes the operating parameters of the rectifying transistors dynamically by adjusting their gate bias voltages based on feedback from the output. This parameter modulation allows the transistors to operate in different regions (linear vs. saturation) depending on the input power level, achieving both high sensitivity at low power and high efficiency at high power, unlike fixed-parameter diode-based rectifiers.
Solution Approach 2:
The patent transforms the static rectification process into a dynamic one by continuously adjusting the bias conditions of the rectifying transistors. This dynamic operation enables the circuit to optimize its performance across varying input power levels, achieving both sensitivity and efficiency that static diode-based circuits cannot simultaneously provide.
3Adaptability or versatility
If feedback bias control is implemented, then operating range is extended, but device complexity increases
Solution Approach 1:
The patent implements a feedback control system that monitors the output voltage and adjusts the gate bias signals accordingly. This feedback mechanism extends the operating range by preventing reverse leakage at high power levels while maintaining sensitivity at low power levels. The complexity introduced is minimal, using standard feedback components and control logic that can be integrated into existing rectifier designs.
Solution Approach 2:
The rectification circuit performs self-regulation through the feedback mechanism, automatically adjusting its own bias conditions based on output measurements. This self-service capability extends the operating range without requiring external control systems, as the circuit autonomously optimizes its performance across different input power levels through internal feedback control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves a peak RF-to-DC power conversion efficiency of 75% and maintains efficiency higher than 40% over a 16 dB dynamic range of input RF power levels, while providing superior sensitivity and reducing reverse leakage, thus extending the operating range of wireless power receivers.
Implementation Method 1
a fully cross-coupled rectification circuit including a pair of forward rectifying transistors
Data Source
AI summary
Various examples are provided related to radio frequency (RF) to direct current (DC) power conversion. In one example, a RF-to-DC converter includes a fully cross-coupled rectification circuit including a pair of forward rectifying transistors and a feedback circuit configured to provide feedback bias signals to gates of the pair of forward rectifying transistors via feedback branch elements. In another example, a method includes receiving a radio frequency (RF) signal; rectifying the RF signal via a fully cross-coupled rectification circuit including a pair of forward rectifying transistors; and providing a DC output voltage from an output connection of the fully cross-coupled rectification circuit, where gating of the pair of forward rectifying transistors is controlled by feedback bias signals provided to gates of the pair of forward rectifying transistors via feedback branch elements.